A lifting device for vehicle-mounted cargo is disclosed. The lifting device includes a loading frame having a loading space storing cargo and sealed sides except an exit; a lifting floor installed in the bottom of the loading frame and forming a floor surface of the loading frame; a lifting cylinder lifting the lifting floor while a cylinder housing is supported to the loading frame and a cylinder load is supported to the lifting floor; a control module installed in the loading frame and controlling the operation of the lifting cylinder; and a plurality of legs separating the loading frame from the ground by being combined with the bottom of the loading frame. It also includes a guide column composed of an external pipe supported to the inside of the loading frame and an internal pipe inserted into the external pipe to be able to slide and having its bottom combined with the lifting floor; and a leg holder composed of a C holder formed on the outer surface of the external pipe and holding the outer surface of a leg separated from the loading frame and a locking member preventing the leg held by the C holder from being separated by locking an opening of the C holder.
